Energy company St1’s geothermal heat production project is moving on to the next phase in Espoo. A giant drilling rig with auxiliary systems have been assembled in the area of a Fortum heat plant in Otaniemi, and the drilling of deep wells for Finland's first geothermal pilot plant will begin soon.

In February, St1 Deep Heat Oy made an investment decision to construct a geothermal heat pilot plant in Otaniemi. The exploration drillings performed in the summer of 2015 proved that the area is promising for heat production based on natural bedrock heat.

Strada Energy, the company responsible for the drilling of the deep-rock wells, has assembled a massive drilling system in the area. The system was brought to the site in 58 truck loads. The drill is over 50 metres high and its hoisting capacity is over 400 tonnes. The electricity grid connection of the electrically operated drill is 6.3 MW. The drill will be operated in one shift by five persons, part of whom are St1's own staff.

The drilling of two seven-kilometre deep production holes will begin in the next few days, and the entire multi-stage process will take approximately six months. After the first hole has been completed, a stimulation phase will be initiated to define the precise location of the second hole in order to create an optimal flow of water between the two holes. These geothermal holes and the natural cracks in the bedrock will function as underground heat exchanges, which will be connected to the overground heat plant systems via a pipework. Just below ground level, the drill holes will be over 100 centimeters in diameter and in their deepest position a little over 20 centimeters. During the construction stage, the project will employ up to 50 people, most of whom come from Finnish companies.

The heat pilot plant is estimated to be completed in 2017. It is estimated to produce up to 40 megawatts of geothermal heat, which Fortum will buy to cover up to 10 per cent of the district heating demand in the Espoo area.

"Research and development and new energy solution demonstrations are critical if we really want to boost Finland's economic growth and replace imported fossil energy with domestic solutions. This geothermal heating pilot project is fully aligned with our strategy; the revenue from our traditional oil business enables us to make increasing investments in local renewable energy production," says Mika Anttonen, Chairman of the Board of Directors of St1.

"This geothermal heat project is a key part of Fortum's plan to shift to carbon-neutral district heating in Espoo by 2030. In addition to geothermal heat, we will diversify our district heating production by using wood-based fuels and waste heat. This will enable us to significantly reduce the carbon dioxide emissions of our heat production and to offer cleaner district heating for the citizens of Espoo," says Heli Antila, Chief Technology Officer at Fortum.

Jukka Mäkelä, Mayor of the City of Espoo, is very pleased with the innovative pilot project between St1 and Fortum. "In our strategy for 2013–2017, the Espoo Story, we have defined that the City of Espoo will be a forerunner in preventing climate change. Geothermal heat product will strengthen our role in reducing emissions and preventing climate change,” he said. According to Mäkelä, this project is an excellent example of cooperation within Espoo Innovation Garden as well as the opportunities provided by the Länsimetro development corridor as a research, development and testing platform. "This is what Finland needs now," he says.

The fully emission-free geothermal heat could be the giant leap towards abandoning fossil fuels in heat production. District heating based mainly on fossil energy is the most common type of heating in Finland. As a result of this pilot project, bedrock could become a renewable energy source that can be utilised in the existing district heating network. The Espoo project is one of Finland's spearhead projects in the field of renewable energy. It has received an investment subsidy from the Ministry of Employment and the Economy. Furthermore, Tekes – the Finnish Funding Agency for Innovation supports scientific research connected to this project in order to develop competences in this field in Finland.